More particularly, the invention concerns, amongst these backrests, those that comprise a rigid structure having a front face and a rear face, the rigid structure being provided with a through hole delimited by a contour and an anchoring system comprising an anchor rod disposed on the side of the front face of the rigid structure, the anchor rod extending across the through hole in order to permit to a coupling member belonging to the child seat to be anchored on the anchor rod via the rear face of the rigid structure.
These vehicle seat backrests are particularly suitable for allowing the attachment in removable manner of child seats comprising three anchor points. Two of these anchor points are usually situated on the bottom portion of the child seat, and these two anchor points are intended to be inserted between the padding of the squab and the padding of the backrest to be clipped or anchored to anchorages secured to the vehicle floor or to the rigid structure of the vehicle seat. The third anchor point is, for its part, formed by a hook belonging to a strap attached to the top portion of the child seat. This third anchor point is anchored to the anchor rod having two ends which are directly welded onto the front face of the rigid structure of the backrest and more particularly onto the contour of the through hole of the rigid structure. Naturally, in this case, the padding intended to cover the rigid structure of the vehicle seat backrest has, in its rear portion, a recess allowing the hook to be anchored to the anchor rod when the child seat is attached to the vehicle seat backrest.
Nevertheless, this anchoring system only formed by the anchor rod whose two ends are directly welded to the rigid structure of the backrest does not give full satisfaction because these spot welds which are only located onto the ends of the anchor rod may be insufficient to retain the hook of the strap when the child seat exerts heavy stresses on the said anchor rod situated on the rear face of the vehicle seat backrest.